The present invention relates to a reflective liquid crystal display apparatus, which can realize a bright image display using no back light.
An example of a conventional reflective liquid crystal display apparatus is disclosed in JP-A-8-184846 (1996).
FIG. 15 is a cross section of the conventional reflective liquid crystal display apparatus, wherein switching devices 60, an insulating layer 35, and a reflecting electrode 27 are formed sequentially on an insulating substrate 11. Color filters 72 and a transparent electrode 26 are formed on another transparent insulating substrate 12. The apparatus is formed so that a liquid crystal material 71 is interposed between the two substrates. Unevenness on the surface of the insulating layer 35 is formed by etching. The etching process here refers to a series of processes comprising the steps of coating with a resist, photolithography, etching, and stripping the resist. Subsequently, contact holes 34 for electrically connecting the reflecting electrode 27 and a source electrode 25 are formed by further etching. As explained above, the shape of the unevenness affects the contour of the surface of the insulating layer 35, thereby producing a corresponding unevenness on the surface of the reflecting electrode 27, which is formed on the surface of the insulating layer 35. The reflecting electrode 27 has a light scattering property based on this unevenness.
In FIG. 15, each switching device includes a gate electrode 22, an insulating layer 31, a semiconductor layer 51, and a drain electrode 24. On the lower substrate 11, there is an insulating layer 33 in contact with the liquid crystal layer 71, and the transparent electrode 26 is provided on the color filter 72. A black matrix 73 is formed on the transparent insulating substrate 12.
Another reflective type liquid crystal display apparatus is disclosed in JP-A-9-54318 (1997). A schematic cross section of part of this reflective type liquid crystal display apparatus is shown in FIG. 16. A switching element 60, an insulating layer 32, and a reflecting electrode 27 are formed on an insulating substrate 11, sequentially. In accordance with this structural arrangement, unevenness is formed on the surface of the reflecting electrode 27.
In this regard, a pattern of islands is previously formed with the material forming the switching element 60 in the region wherein the reflecting electrode 27 is arranged.
In this way, an unevenness is formed on the surface of the reflecting electrode 27, eliminating the need to form the unevenness on the surface of the insulating layer 32 by etching.